But now I got some problem when I need to rotate the camera. In other word, I need to modify some value into the MatCamera matrix to realize a rotation around an axis.
I know that Quaternion could be the best utility to proceed but HOW to use it ?

How can I extract the present X rotation inside the MatCamera matrix to modify it or increment it ? After this, I believe that I need to convert it to a Quaternion and an axis ? How can add this rotation to my MatCamera matrix ?

Thanks to help me...
I'm desperate...

PS :I just want to know if it's the right way to get the UP vector of the ModelView matrix